Diversity of Life

The Eukaryotes II: Plants

• How are plants similar to algae? How are they different?

• Gallery

Plant adaptations

1. Plants are multi-cellular
2. Plants have true tissues and organs
   • Epidermal tissue ('skin')
   • Conductive/transport tissue (circulation)
   • Support tissue (connective)
   • Dividing tissue (meristem)
3. Plants are adapted for terrestrial life
   • Roots for nutrient/water absorption
   • Shoots for photosynthesis
   • Protected embryo (seeds)
   • Waxy cuticle on epithelium
4. Plants exhibit alternation of generations
   1. Sporophyte (2N)
   2. Produces spores (Meiosis)
   3. Spores give rise to Gametophyte (N)
   4. Produces gametes (eggs + sperm)
   5. Fertilization = embryo (2N)
   6. Embryo becomes sporophyte

Plant Diversity

Nonvascular plants

Gametophyte is dominant. Sporophyte grows on gametophyte. Sperm are flagellated.

1. Bryophytes
   1. Mosses
      • Life cycle
      • Capsule, seta
   2. Hornworts
   3. Liverworts

Don't get confused! The following are not true mosses!

• Spanish moss
• Club moss
• Reindeer moss
• Irish moss

Seedless vascular plants

Gametophyte is tiny and free-living. Sporophyte is dominant.

1. Ferns
   1. Fronds
   2. Fiddleheads
   3. Sori
   4. Life cycle
2. Club mosses
3. Horsetails

Seed-bearing plants

Sporophyte is dominant. Gametophyte exists within cone or flower (male/female)

1. Gymnosperms
   1. Conifers
      • Cones (male and female)
      • Life cycle
   2. Gingko
      • Leaf
   3. Cycads
2. Angiosperms
   • Life cycle
     • Flower
     • Fruit
   1. Monocots
      • Lilies, grasses, palm trees
      • Petals in 3s; parallel veined leaves;  fibrous roots
   2. Dicots
      • Cactus, oak, maple
      • Petals in 4s or 5s, branched veined leaves, taproots

Unusual plants

• Nonphotosynthetic plants (e.g. Broomrape & witchweed)
• Epiphytes (e.g. bromeliads)
• Medicinal plants (curare, digitalis, morphine, atropine)
• Meat-eating plants (e.g. Venus flytrap)
• Xerophytes (e.g. cacti)
• Rafflesia